Correlation between magnon and magnetic symmetries of hexagonal RMnO₃ (R = Er, Ho, Lu)

The correlation between the magnon scattering and the magnetic symmetries of hexagonal RMnO₃ (R = Er, Ho) thin films and LuMnO₃ single crystal was studied through the 2D Correlation Spectroscopy (2D COS) and Perturbation-Correlation Moving Window 2D (PCMW2D) Correlation Spectroscopy which were performed on the temperature-dependent Raman spectra of RMnO₃ (R = Er, Ho, Lu). From the Raman spectra, we observed much stronger intensity and more asymmetrical magnon peak in LuMnO₃ single crystal than in ErMnO₃ and HoMnO₃ thin films. While the ratio between magnon and phonon's linewidth of LuMnO₃ and HoMnO₃ display an anomalous behavior, that ratio of ErMnO₃ is almost stable. The result from PCMW2D also supports these results. In addition, our 2D COS analysis showed that there are more overlap peaks in broad four-spin flipping magnon peak in LuMnO₃ than that in ErMnO₃ and HoMnO₃. The differences of hexagonal RMnO₃ (R = Er, Ho, Lu) in magnon scattering are very similar to the actual differences of the magnetic symmetries of these compounds. Therefore, we suggest that the magnon scattering of hexagonal RMnO₃ is strongly correlated with the magnetic symmetries of these materials.